Mesh count and halftone dots are locked together

Screen printing a halftone image means reproducing a grid of tiny dots through a mesh whose threads also form a grid. If the two grids are too close in scale, the mesh cannot hold the dot, and the interference between them produces visible patterning called moiré.

The industry rule of thumb is the 4:1 ratio: mesh count should be at least four times the halftone line screen.

minimum mesh (threads/inch) ≥ 4 × LPI

What that gives you

Halftone LPI	Minimum mesh	Practical mesh	Typical job
35	140	156–160	Bold graphics, coarse detail, dark garments
45	180	196–200	General garment printing
55	220	230–250	Finer detail, standard sim-process
65	260	280–305	Detailed graphics on light garments
85	340	355–380	High-detail work, requires tight control

Working the other way — you have 305 mesh and want to know the maximum safe LPI — divide instead: 305 ÷ 4 = 76 LPI. Round down rather than up; the ratio is a minimum, not a target.

The other variables that change the answer

• Ink type. Plastisol sits on top of the fabric and holds finer detail than water-based ink, which penetrates and spreads. Water-based work often needs the ratio pushed to 5:1.
• Mesh colour. Dyed (yellow or orange) mesh reduces light scatter during exposure, so it holds finer detail than white mesh of the same count. For work above 55 LPI, dyed mesh is close to essential.
• Mesh thread diameter. Two meshes both sold as “200” can differ in thread thickness: thinner threads mean wider openings, more ink flow, and better detail retention.
• Fabric. Coarse or textured garments need more ink to cover, which pushes you towards a lower mesh and therefore a coarser line screen.
• Moiré angle. Standard halftone angles (typically 22.5° for single-colour work) exist to keep the dot grid from aligning with the mesh. Rotating the artwork a few degrees is sometimes the fix when everything else is correct.

Threads per inch versus threads per centimetre

Mesh is sold in both. The conversion is tpi = tpc × 2.54, so a 120 thread/cm mesh is about 305 threads/inch. The two are not interchangeable in conversation — “120 mesh” means two very different screens depending on which unit the supplier uses, and this is a common source of ordering errors.

Common questions

Can I print a higher LPI than the ratio allows?

You can try, but you will lose dots. Fine highlight dots fall through the mesh openings entirely, so highlights blow out and the tonal range collapses. The 4:1 ratio is a practical limit, not a conservative one.

Does higher mesh always mean better quality?

No. High mesh lays down less ink, so coverage on dark garments suffers and you may need multiple passes or a white underbase. Choose the mesh for the job: coarse for bold coverage on darks, fine for detail on lights.

Why did my print come out with a pattern in the halftone?

Almost always moiré from insufficient mesh-to-LPI ratio, or a dot angle aligning with the mesh. Check the ratio first, then the angle, then the mesh colour.